CAIP 2017, the 17th international Conference on Computer Analysis of Images and Patterns, will take place from 22th – 24th August 2017 in Ystad, Sweden. The 4th Workshop on Recognition and Action for Scene Understanding (REACTS), organised by partners of the CLARC PDTI, is a satellite event of CAIP which will be held also in Ystad on August 25. Scene Understanding is now a popular topic in Computer Science, which combines abilities such as perception, analysis and interpretation of both indoor and outdoor scenes. The REACTS Workshop proposes in this new edition to focus on cooperative and social robots, and how to endow within them the abilities of understanding human activities and intention. A tentative agenda is available below, for more information on how to attend the workshop, please visit this page.